A few quick, interesting facts about a different topic each entry. It's like an apple a day: pleasant, good to have, and pocket-sized.

Friday, June 5, 2009

Apple #389: Sequoia Trees

One of the things I did on my trip to California was go with a friend of mine to Yosemite. There are many enormous things to see there -- huge rocks, huge trees, huge waterfalls. All of it is so beautiful, you kind of can't believe it. After I was there for a while, I kind of got used to it. I'd be walking along, eyes on the path, and then I'd look up and it would all still be there, and it would astonish me all over again. Still enormous, still covered with gigantic green trees, still sitting there like it was perfectly everyday to be so enormous and so magnificent.

I'm realizing as I type this that I need to do an entry about Yosemite. Since I was introduced to the national park before I saw the sequoia trees, I should do the Yosemite entry first. But a few Daily Apple fans have been clamoring for the sequoia tree entry, so I'm doing this one first.

There are a number of sequoia groves in Yosemite, and the one I went to was the Mariposa Grove, near an area called Wawona. You have to walk into the woods a ways, so that's what we were doing, and then my friend pointed up ahead, and I looked where he was pointing, and I saw the first sequoia tree. My jaw dropped and I said, "Whoa." That was my very articulate, intelligent response. I took a photo or two, stared some more. Then I said, "I know why they call this place Wawona. Because that's all you can say when you see these trees."

The first sequoia I saw. I took two photos of this tree and later spliced them together. You can probably detect the line where the photos meet. I could have Photoshopped that out, but I decided to leave it in. It's hard to convey just how tall these things are. I thought if you could see where the two photos join, that might give you an idea of how much -- or how little -- of one tree would fit into the frame at a time.
(Photo by your Apple Lady)

Sequoias grow as high as 310 feet tall. The tallest sequoia in the grove where I was is 290 feet.

The largest giant sequoia is over 40 feet in diameter around its base.

There are other trees that grow taller (their relatives, the coastal redwoods, may grow up to 378 feet). There are other trees that are also wider around (a Montezuma cypress in Mexico has exceeded 50 feet around).

But in terms of total volume, sequoia trees are the largest living things on earth.

They are also the heaviest living things. A sequoia may weigh as much as 2,000 tons. A blue whale, by comparison, only weighs 200 tons.

Here's another attempt to give you an idea of the size of these trees. The smallish pink and blue things to the right of the tree are people. Not children, adults.
(Photo by the Apple Lady)

Sequoias only grow on the western side of the Sierra Nevada mountain range, in about 70 groves.

The trunk of the second sequoia, I think. In the background on the right, very small, are people looking at the tree. The small blue rectangle next to the right of the tree is a van parked behind the tree.
(Photo by the Apple Lady)

The trees all had signs, like the one in the above photo, cautioning people not to stand too close. This is because the root system does not extend deep underground like you might thing, but it's all very close to the surface. Sequoia botanists estimate that 95% of a sequoia's roots are within 3 feet of the surface.

When the buildup of soil and stuff gets to be too deep and the roots too far below the surface to get necessary nutrients, the tree will send out new roots. Some of those roots extend from the ends of the old root system, but some of them extend from the central base of the tree, but above the older roots and closer to the surface of the ground. It is these fresh, new roots that park rangers are trying to protect by telling people not to stand too close to the tree.

Despite the fact that the roots are so close to the surface, the trees don't fall over because the root systems extend far, far from the trunk. Sometimes the roots can reach over half an acre.

The bottom part of all these trees was hollowed out, to some extent or other, and blackened. This is where forest fires have burned away the bottom core of the trees.

Sequoia trees don't burn as easily as other types of trees because the bark is full of little air pockets.

Around the side of the trunk of the second sequoia. The charred section (burn scar) on this tree is relatively smaller, compared to some of the others. But they all have a similar flame-like shape to them.
(Photo by the Apple Lady)

The results look pretty precarious, especially given the height and volume of these trees. But fire is essential to the health and reproduction of the sequoia. Forest fires clear away the smaller trees that compete for sunlight that the sequoias need, and the ash from burned branches and leaves provides nutrients that are essential to the sequoia.

Perhaps most importantly of all, fires provide heat. The sequoia's cones will not open and disperse their seeds unless temperatures reach a certain point. So the sequoias need fire in order to reproduce.

The cones can be very patient, waiting on the branches for the right fire to come along. Some of the cones remain closed up for as long as 20 years.

A large sequoia may have about 11,000 cones. In a year when its cones dry out and open, the seeds scattering everywhere, the tree will disperse an estimated 300,000 to 400,000 seeds. The seeds may fly as far as 600 feet from the tree.

The reason that fires affect sequoias in this particular way -- by burning away the lower core of the tree -- is because that inner core is actually dead. The living part of the tree is at its outer edges (called the cambium), just beneath the bark. While the loss of the center does weaken the tree structurally, the sequoia can grow quite nicely without it.

I was so amazed by these trees that were standing with no center, just about, that I thought surely they must grow in a different way than other types of plants. How could a tree survive without its middle?

The sequoia on the right is known as the Clothespin tree, for obvious reasons. Yup, this tree is still alive and still growing.
(Photo by the Apple Lady)

But I have just learned that sequoias grow the same way that all trees do, which is to say that all the growing action happens in the rings around the very center. The very center is the pith, and not much goes on there. The rings -- the xylem and phloem -- are where new cells that hold the nutrients are added, and the outer layer -- the cork, which we call bark -- expands to hold the innards.

Like many other plants, over time the sequoia also develops another protective layer under the cork (bark) called the periderm. The periderm is made of cells that are very similar to the cork cells, plus they have a special waterproofing capability, believe it or not. The sequoia differs from other plants in that its periderm and its cork are especially thick -- up to several feet thick.

The thickness of those tough outer layers is what protects the sensitive growing parts (cambium) and helps the tree keep standing even after fires have burned out the pith.

Sequoias also happen to be loaded with tannins, which are a type of antioxidant that plants have. (You may have encountered tannins in wine, which are what give the wine its puckery, almost bitter flavor. Tannins are present in the grapes, especially in unripe green ones.)

The superabundance of tannins is what gives the sequoia wood its distinctive reddish-orange color.

After the bottom part of the tree gets burned away, the tannins leak down into that burned area and sort of coat it, almost like sap. It's not sticky like sap, but it is moist. To any animals or insects that might consider burrowing into the wood, the tannins taste very astringent and are for some animals toxic. So the tannins help protect that exposed wood against invaders.

What one of the burn scars looks like up close. The glistening areas are where the tannins are leaking out of the tree.
(Photo by the Apple Lady)

The same burn scar on the same tree, looking up. Judging by how high up these trees get burned, those fires must be no joke.
(Photo by the Apple Lady)

The dark stuff on the left side of that tree is not a shadow, that's where the bark got charred from some past forest fire. This is another indication of how high those flames must leap. That tree isn't sequoia; I think it's a sugar pine.
(Photo by the Apple Lady)

The roots of a sequoia that fell over 150 years ago. These trees don't really decay the way most other trees do because of all the tannins in the wood. Fungi and bacteria that normally break down fallen trees do not like the tannins, so they don't go to work on fallen sequoias -- that is, not until after many years' worth of rains and snows have begun to wash off the tannins. You can see some green mossy stuff starting to grow on some of these roots.
(Photo by the Apple Lady. I don't know any of the people in this photo.)

Because of their resistance to fire and insects and decay, sequoia trees live for a really long time. The oldest known sequoia is estimated to be about 3,200 to 3,500 years old. When you're talking multiple thousands of years, what's a few hundred, give or take?

Fossils show that sequoia trees used to grow all over the place in the Jurassic period -- the time of the dinosaurs.

If a sequoia tree still has a bunch of dead branches on it on the lower section of the tree, that means it's younger than 100 years old. Mature sequoias generally shed their dead branches (or the branches get burned off) and are without any branches until about 100 to 150 feet up the trunk.

Sequoias survived the logging craze of the late 1800s, first of all because the bark is so thick it dulled the loggers' saws before they could get very far. But when the loggers got the trees cut down, they discovered that the wood is actually very brittle. Most of the sequoias that were cut down were used to make stakes for grape plants in vineyards because the wood was too brittle to be used for much else. When cut into planks, it warps, so it's no good for lumber.

The brittleness of the wood is often what causes sequoia trees' downfall (ha ha). In spite of their protection against fire and insects and fungi and bacteria, sometimes the burn scars can be so extensive that the remaining wood can't support the tree as well anymore and when a strong wind comes up, the wood cracks and the tree falls over.

The word sequoia comes from the name of the Cherokee man who wrote down the Cherokee alphabet, or syllabary.

Sequoyah, the man who invented the written form of his Cherokee language.
(Image from the National Park Service)

During a hunting accident in which his foot was permanently he was given the name "pig's foot," which is Seqouyah (sometimes Sikwayi) in Cherokee.

So the sequoia trees are essentially called "pig's feet."

But how did this man become connected with gigantic trees? He never even lived in California.

Sequoyah was born in Tennessee and grew up to be a fur trapper. After his accident, he couldn't trap anymore, so he learned blacksmithing and silversmithing. He got married and his family moved to Georgia.

In the War of 1812, he fought for the United States against the British and the Creek tribe.

While he was in the military, he observed his fellow soldiers reading and writing. He was inspired, not to learn English, but to write down his own language. He was convinced if the Cherokee had a written version of their language, they would have more power in the eyes of white people.

He experimented with pictographs and tried making new letter shapes based on the symbols in English, Greek, and Hebrew alphabets. After twelve years of hard work and with the help of his young daughter, he had represented all the sounds of his language in 86 symbols.

His syllabary caught on quickly, especially because of the way he taught it to others, and it wasn't long before thousands of Cherokee had learned to read and write their own language, which had before only been spoken.

He became very politically active on behalf of his fellow Cherokee, and acted as a diplomat on behalf of his people in Washington, DC.

His goal was to try to unite the Cherokee nation. He died in 1843 while searching for a group of Cherokee that were rumored to have gone south to Mexico.

It is said that one of the ways his memory was honored was by naming the great sequoia trees after him. But I can't find out when the trees were named, or by whom, or why they picked exactly this man.

Now I'm going to stop talking and show you more photos. I saved some of the best for last.

The base of the largest tree in Mariposa Grove, the Grizzly Giant. This photo doesn't give you any sense at all of how big this tree is. It's 209 feet tall, its trunk's circumference is 96 feet, and it was born some time around 700 B.C. This photo gives you a much better idea.
(Photo by the Apple Lady)

Some of the branches of the Grizzly Giant. That biggest branch at the top of the photo is 7 feet in diameter, which is larger than any of the non-sequoia tree trunks in the entire area.
(Photo by the Apple Lady)

Better still, here's a very short video I took panning up from the bottom of the Grizzly Giant to the top.You can even hear the wacky birds in the background. Ah, technology!

What a cool site. I love the idea of pointing out all the hardships that trees endure. I had never thought about trees as survivors of atomic bombs. That's such a compelling photo, and what an equally compelling idea, to follow the progress of the seedlings of those trees.

I'm happy the urge to raze down the grove , cut down the trees to build disposable cots did not engulf you. Its also impressive that at no time during your trip that you felt like claiming the land under those trees for shopping mall development.

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